{
语法百题 解题报告：
 http://git.oschina.net/et0662/sznoi-grammar/ 
}
var
	even,t:longint;
begin
	even:=0;
	read(t);
	while t<>-1 do
	begin
		if (t mod 2)=0 then inc(even);
		read(t);
	end;
	writeln(even);
end.
